Print control apparatus and method

ABSTRACT

Whether a continuous sheet usable for printing on the basis of first print data and a continuous sheet usable for printing on the basis of second print data are the same or not is determined. If it is determined that they are the same, an image based on the first print data and an image based on the second print data are printed continuously on a continuous sheet. When an image based on the second print data is arranged at an end of a continuous sheet, the second print data is assigned to the beginning of print data to be printed on another continuous sheet.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/960,393, filed on Dec. 3, 2010, entitled “PRINT CONTROLAPPARATUS AND METHOD”, the content of which is expressly incorporated byreference herein in its entirety. This application claims the benefit ofJapanese Patent Application No. 2010-041657 filed Feb. 26, 2010, whichis hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a print control apparatus and methodfor printing on a continuous sheet.

2. Description of the Related Art

Hitherto, a technology for printing an image on a continuous sheet suchas roll paper has been known which detects the remaining amount of acontinuous sheet and executes a print job that uses a less amount ofsheet than the detected remaining amount. (Refer to Japanese PatentLaid-Open No. 2005-169918).

However, the technology disclosed in Japanese Patent Laid-Open No.2005-169918 may waste the difference between the detected remainingamount and the amount of the sheet used by a print job. When a wrongremaining amount is detected, the difference may possibly increase.

On the other hand, in printing up to the end of a continuous sheet, theprintable amount of print data is not unknown until the printingprocessing is actually performed. Thus, preparing the print data to beprinted after replacement of a continuous sheet is difficult before thecontinuous sheet runs out, which may delay the processing.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there are provided aprint control apparatus and method which solve the problems. Accordingto another aspect, there are provided a print control apparatus andmethod which allow use of a continuous sheet without wastes in printingon a continuous sheet and efficient implementation of printingprocessing.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a configuration of an image forming apparatus whichis an example of an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration relating tocontrol in the image forming apparatus in FIG. 1.

FIG. 3 is a flowchart illustrating a flow of processing according tothis embodiment.

FIG. 4 is a flowchart illustrating a flow of processing of determiningthe order of printing pages.

FIG. 5 is a flowchart illustrating a flow of processing in the casewhere sheet runs out during the printing processing.

FIGS. 6A and 6B illustrate the printing order of a plurality of printjobs.

FIG. 7 illustrates assignment of print data.

DESCRIPTION OF THE EMBODIMENT

An Embodiment of the present invention will be described below withreference to drawings. The relative configurations and device forms ofthe components of an apparatus according to the embodiment are forillustration purposes only, and the present invention is not limitedthereto only.

FIG. 1 is a schematic configuration of an image forming apparatus whichis an example of a print control apparatus according to an embodiment.The image forming apparatus illustrated in FIG. 1 only has a printingfunction of printing data received from an external apparatus but maybe, without limiting thereto, one which functions as a copy machinefurther including a reader which scans an image on a copy or amultifunction apparatus further including other functions.

A roll sheet will be described as an example of a recording material(recording medium or recording paper) to be printed. The roll sheet isan example of a continuous sheet, the continuous sheet may not be woundon a roll. The continuous sheet may be automatically cut by an imageforming apparatus or may be cut in accordance with a manual instructionby a user. The recording material is not limited to paper, but variousmaterials may be used if they are printable. The image forming apparatusmay not only print a continuous sheet but also print pre-cut sheetshaving a predetermined size.

The printing method is not limited to ink-jet printing of an image byusing a liquid ink for image printing, which will be described below.The recording agent to be applied to a recording material may be solidink, or recording may be performed by various recording methods such aselectrophotography using toner, sublimation, thermal transfer, and dotimpact. Recording may further be color recording using recording agentsof a plurality of colors or monochrome recording using black (includinggray). Printing may not be limited to printing of a visible image butmay be printing of an invisible image or an image which is difficult tosee. Instead of general image printing, various printing may beperformed such as printing of a wiring pattern, a physical pattern inpart manufacturing, and a base arrangement of DNA. In other words, thepresent invention is applicable to various types of recordingapparatuses if they can apply a recording agent to a recording material.When an operation in printing processing is controlled in the imageforming apparatus in accordance with an instruction from an externalapparatus connected to the image forming apparatus in FIG. 1, theexternal apparatus may be a print control apparatus.

FIG. 1 is a section view illustrating a schematic configuration of theentire image forming apparatus which uses a roll sheet (longercontinuous sheet than a print unit (one page) in the direction ofconvey) as a recording material. The image forming apparatus includescomponents 101 to 115, which will be described below, within oneenclosure. However, those components may be provided separately in aplurality of enclosures.

The control unit 108 contains a controller (including a CPU or MPU), anoutput device of user interface information (a generator of displayinformation or sound information, for example), and control units havingI/O interfaces and is responsible for control over the entire imageforming apparatus.

Two units of an upper sheet cassette 101 a and a lower sheet cassette101 b hold and feed roll sheets. A user mounts a roll sheet (called asheet hereinafter) on a magazine and loads it to the body of the imageforming apparatus. The sheets drawn from the upper sheet cassette 101 aand lower sheet cassette 101 b are conveyed in the a-direction andb-direction, respectively, in FIG. 1. The sheet from either one of thecassettes moves in the c-direction illustrated in FIG. 1 and reaches toa conveying unit 102. The conveying unit 102 conveys a sheet beingprinted in the d-direction (horizontal direction) in FIG. 1 through aplurality of rotary rollers 104. In order to switch the feeding sheetcassette from one to the other, the already drawn sheet is wound backinto the currently used cassette, and the sheet to replace is fed fromthe cassette having the sheet.

A head unit 105 is placed above and faced against the conveying unit102. The head unit 105 holds independent print heads 106 for a pluralityof colors (seven in this embodiment) in the direction of conveying asheet. According to this embodiment, seven print heads are providedcorresponding to seven colors of C (cyan), M (magenta), Y (yellow), LC(light cyan), LM (light magenta), G (gray), and K (black). Other colorsmay be used, or any one or any combination of those colors may be used.

The image forming apparatus causes the print heads 106 to eject ink to asheet to form an image in synchronization with the convey of a sheet bythe conveying unit 102. The print heads 106 are placed at a positionwhere they can eject ink to areas of a sheet without the rotary rollers104 underneath. Instead of direct ejection of ink to a sheet, ink may beapplied to an intermediate transfer member first, and the ink may thenbe applied to a sheet to form an image.

The conveying unit 102, head unit 105, and print heads 106 are includedin a unit for printing of this embodiment.

Ink tanks 109 separately reserve different color inks. From the inktanks 109, inks are supplied to sub tanks through tubes corresponding tothe colors. From the sub tanks, inks are supplied to the print heads 106through tubes.

The print heads 106 have line heads for colors (seven colors in thisembodiment) in the d-direction of convey in printing. The line heads forcolors may be a seamless single nozzle chip or have divided nozzle chipsregularly in a line or in a staggered arrangement. According to thisembodiment, what is called a full multi head is used which has nozzlesin a range covering the width of the print area of a sheet having amaximum size supported by the image forming apparatus. The ink-jetsystem by which ink is ejected from nozzles may use a heater element, apiezoelement, an electrostatic element, or an MEMS element, for example.On the basis of the print data, an ink is ejected from the nozzle of thecorresponding head at the time determined by an output signal from anencoder 103 for convey.

After an image is formed on the sheet, the sheet is conveyed from theconveying unit 102 to a scanner unit 107. In the scanner unit 107, aprinted image and/or special pattern is optically scanned to checkwhether the printed image has any problem or not and/or check the stateof the image forming apparatus including the state of ink ejection. Inorder to check the printed image, the ink ejection state may be checkedby reading a pattern for checking the states of the heads, or thesuccess/failure of the printing may be checked by comparing the printedimage and its original image. The method for checking may be selectedproperly from various methods.

The sheet is conveyed from the vicinity of the scanner unit 107 in thee-direction and is guided to a cutter unit 110. The cutter unit 110 cutsthe sheet into predetermined print unit lengths. The predeterminedprinting unit length depends on the image size to print. For example, anL-size photo has a length of 135 mm in the direction of convey, and theA4 size has a length of 297 mm in the direction of convey. The cutterunit 110 in simplex printing mode cuts a sheet into pages but may notcut into pages with some kinds of print job. The cutter unit 110 induplex printing mode does not cut the first side (which is the side tobe printed first such as the front surface) of a sheet into page units,but an image is continuously printed to a predetermined length. Thesheet is then cut into page units after the second side (which is theside to be printed afterward such as its back surface) is printed. Thecutter unit 110 does not typically cut for every one image in one sideprinting mode or in back surface printing in duplex printing mode. Thecutter unit 110 does not cut until a sheet is conveyed to apredetermined length. Another cutter device cuts the sheet for every oneimage (or one page) by a manual operation, for example. When the sheetis required to cut in the width direction, another cutter device is usedto cut.

The sheet conveyed from the cutter unit 110 is conveyed in thef-direction in FIG. 1 within the unit and is conveyed to a back surfaceprinting unit 111. The back surface printing unit 111 printspredetermined information on the back surface of a sheet when an imageis to be printed only on one side of the sheet. The information to beprinted on the back surface of a sheet may include information such as aletter, symbol and code corresponding to each print image, (such as anorder management number). When the print heads 106 print an image for aprint job in duplex printing mode, the back surface printing unit 111prints information as described above in the area excluding the area onwhich the print heads 106 print an image. The back surface printing unit111 may use impression of a recording agent, thermal transfer, ink-jetor the like.

The sheet having passed through the back surface printing unit 111 isnext conveyed to a drying unit 112. The drying unit 112 heats the sheetpassing in the g-direction in FIG. 1 within the unit with warm currentof air (heated gas (air)) in order to dry a sheet to which ink has beenapplied in a short time. Instead of the use of warm current of air,various drying methods may be used such as use of cold air, heating byusing a heater, natural drying simply by waiting, and irradiation ofelectromagnetic waves such as an ultraviolet ray. The cut sheets havingprinting unit lengths pass through the inside of the drying unit 112,are conveyed in the h-direction in FIG. 1 and are then conveyed to asorter unit 114.

The sorter unit 114 holds a plurality of trays (18 trays in thisembodiment), and sorts sheets into trays by the length of print units,for example. Each tray has a tray number. In the sorter unit 114, asheet passing in the i-direction in FIG. 1 within the unit is dischargedto the tray corresponding to the tray number set for each printed imageby checking the vacancy of the trays and/or whether the trays are fullof sheets or not with sensors provided on the trays. The cut sheets maybe discharged to the tray designated by the source (host apparatus) ofthe print job or to an arbitrary vacant tray designated by the imageforming apparatus. A predetermined number of sheets may be discharged toone tray. For a print job handling more sheets than the predeterminednumber of sheets, the sheets may be discharged over a plurality oftrays. The number, size, type or the like of sheets dischargeable to atray may depend on the size (type) of the tray, for example. In FIG. 1,the vertically (top-to-bottom) aligned trays (called large trayshereinafter) may accept both large-size (which is larger than L-sizesuch as A4 size) sheets and small size (L-size) sheets. The horizontally(left-to-right) aligned trays (called small trays hereinafter) mayaccept small-size (L-size) sheets but do not accept large-size sheets.The large trays may accept more number of output sheets than the smalltrays.

The states of discharging sheets or completion of discharging may beidentified by a user from an indicator (such as an LED). For example, aplurality of LEDs which emit different colors may be provided for thetrays, and various states of the trays may be notified to a user withthe colors of the lighted LEDs or either lighting state or blinkingstate. The plurality of trays may have a priority order. The imageforming apparatus performing a print job assigns discharged sheets tovacant trays (without sheets) in the priority order. At default, thehigher large trays have higher priority levels. The small trays on theleft-hand side have higher priority levels. The large trays have higherpriority levels than the small trays. A higher priority levels may bepreset to the trays from which a user can more easily remove sheets. Thepriority order may be changed properly in accordance with an operationby a user.

A sheet winding unit 113 winds a sheet having its front surface printedwithout being cut by pages. In duplex printing mode, a sheet having animage on its front surface first is not cut into page units by thecutter unit 110 but is cut after the printing on the continuous frontsurface finishes. The sheet having its front surface printed passes inthe j-direction in FIG. 1 within the unit and is wound by the sheetwinding unit 113. The wound sheet having images for a series of pages onits front surface is turned to make the opposite side of the frontsurface printable, that is, the surface facing the print heads 106 isreversed. Then, the sheet is conveyed again in the k-direction in FIG. 1within the unit. Images are printed on the opposite back surface of thefront surface of the conveyed sheet. In normal simplex printing mode, asheet having images printed is not wound by the sheet winding unit 113but is conveyed to the sorter unit 114.

In this way, in duplex printing mode, the sheet winding unit 113 is usedto wind a sheet, and the sheet is reversed to have its back surfaceprinted. Thus, sheets are discharged to the sorter unit 114 with thesides being different from each other between simplex printing mode andduplex printing mode. In other words, since, in simplex printing mode,the reverse of sheet by using the sheet winding unit 113 is notperformed, the sheet having an image of the first page printed isdischarged with the image of the first page facing down. In one printjob handling a plurality of pages, a sheet of the first page isdischarged to a tray first, and sheets of the subsequent pages aresequentially discharged and are piled. This kind of discharge is calleda face-down discharge. On the other hand, in duplex printing mode, sincethe sheet winding unit 113 is used to reverse a sheet, the sheet havingan image of the first page printed is discharged with the image of thefirst page facing up. In one print job outputting a plurality of sheets,the sheet containing the last page is discharged to the tray first, andthe preceding sheets are sequentially discharged and are piled. Finally,the sheet having an image of the first page printed is discharged. Thiskind of discharge is called a face-up discharge.

An operating unit 115 accepts various operations by a user and/ornotifies a user of various kinds of information. For example, a printingcondition for each job order can be checked including the tray havingthe sheet having the image designated by a user printed and/or whetherthe image is being printing or has completed printing. The operatingunit 115 may further allow a user to check the states of the apparatussuch as the remaining amount of ink and the remaining amount of sheetand/or operate and/or check for instructing to perform maintenance ofthe apparatus such as head cleaning.

FIG. 2 is a block diagram illustrating a configuration relating tocontrol in the image forming apparatus illustrated in FIG. 1. An imageforming apparatus 200 is the image forming apparatus illustrated in FIG.1.

A main controller 201, image processing unit 207, scanner control unit208, engine control unit 209, motor control unit 210, head control unit211, and sorter control unit 212 illustrated in FIG. 2 are mainlyincluded in the control unit 108. These components are communicable witheach other via a system bus 214.

The main controller 201 includes a central processing unit (CPU) 202, aROM 203, a RAM 204, an external I/F 205, and an HDD 206, and thesecomponents are communicable with each other via a system bus 213. Themain controller 201 is responsible for control over the entire imageforming apparatus 200.

The CPU 202 is a central processing unit being a microprocessor(microcomputer) and controls over the entire operations by the imageforming apparatus 200 in accordance with the execution of a program orthe start of hardware. The ROM 203 stores a program to be executed bythe CPU 202 and/or fix data that are necessary for operations by theimage forming apparatus 200. The RAM 204 may be used as a work area bythe CPU 202, may be used as a temporary storage area for various receivedata or may store setting data. The external I/F 205 connects the imageforming apparatus 200 to an external apparatus. The external I/F 205 maybe either local I/F or network I/F. The external I/F 205 may handleconnection through wire or by radio. The HDD 206 may allow storingand/or reading a program to be executed by the CPU 202, for example,print data, setting information that is necessary for operations by theimage forming apparatus 200 to/from the contained hard disk. Instead ofthe HDD 206, other large-capacity storage device may be used.

The image processing unit 207 performs image processing includingexpansion (conversion) of print data (such as data written in pagedescription language) to be handled by the image forming apparatus 200to image data (bitmap image). The image processing unit 207 converts thecolor space (such as YCbCr) of image data contained in input print datato the standard RGB color space (such as sRGB). The image processingunit 207 performs various kinds of image processing on image data,including the resolution conversion to a valid number of pixels (orprintable number of pixels by the image forming apparatus 200), imageanalysis, and image correction, for example. The image data acquired bythe image processing may be stored in an internal RAM, or the RAM 204 orHDD 206. The image processing unit 207 includes a CPU, a ROM, and a RAM,which are connected to each other via a system bus, like the maincontroller 201. The CPU performs the image processing as described abovein accordance with a program stored in the ROM.

The scanner control unit 208 controls an image sensor in accordance withthe control command received from the CPU 202, for example, and reads animage on a sheet, acquires analog luminance data of red (R), green (G)and blue (B) and converts them to digital data. The image sensor may bea CCD image sensor, CMOS image sensor or the like. The image sensor maybe either linear image sensor or area image sensor. The scanner controlunit 208 instructs the driving of the image sensor and acquires thecondition of the image sensor on the basis of the driving. The scannercontrol unit 208 then analyzes the luminance data acquired from theimage sensor to detect an ejection failure from the print heads 106 andthe cut position of a sheet, for example. The sheet determined by thescanner control unit 208 as an image correctly printed undergoes dryprocessing of drying ink on the sheet and is discharged to thedesignated tray of the sorter unit. The scanner control unit 208 alsoincludes a CPU, ROM, and RAM which are connected to each other via asystem bus, like the main controller 201. The CPU performs scanningprocessing as described above in accordance with the program stored inthe ROM.

The engine control unit 209 controls processing of printing an imagebased on print data on a sheet in accordance with a control commandreceived from the CPU 202. The engine control unit 209 in printingprocessing controls a head control unit 211, a motor control unit 210, ascanner control unit 208 and a sorter control unit 212 to perform aseries of printing processing operations. In other words, the enginecontrol unit 209 controls application of ink by using the print heads106, convey of a sheet, check on success/failure of image printing byusing the image sensor and sorting by using a tray or trays of thesorter unit 114. The control command, data, status signals or the likemay be transmitted and received to/from the main controller 201 via thesystem bus 214. The engine control unit 209 also includes a CPU, a ROM,and a RAM which are connected to each other via a system bus, like themain controller 201, and the CPU controls printing processing asdescribed above in accordance with the program stored in the ROM.

In accordance with a control command received from the engine controlunit 209, the motor control unit 210 instructs to drive a draw-outroller which draws a sheet and instructs to drive a conveying rollerwhich conveys a drawn sheet and controls motors to implement thoseoperations. The motor control unit 210 further acquires the rotationcondition of the conveying rollers, conveys and stops a sheet at aproper speed and through a proper path and measures the length of theconveyed sheet. The motor control unit 210 also includes a CPU, a ROM,and a RAM which are connected to each other via a system bus, like themain controller 201. In accordance with the program stored in the ROM,the CPU controls processing relating to motors as described above.

The head control unit 211 may instruct the print heads 106 for differentcolors to eject ink, sets ejection timing for adjusting the dotpositions (the positions of ink droplets) on a recording medium, andperform adjustment on the basis of the acquired state of the headdriving. In accordance with a control command received from the enginecontrol unit 209, the head control unit 211 controls driving of theprint heads on the basis of print data and causes the print heads toeject ink to form the image on a sheet. The head control unit 211 alsoincludes a CPU, ROM, and RAM which are connected via a system bus, likethe main controller 201. In accordance with a program stored in the ROM,the CPU controls processing using the print heads 106 as describedabove.

The sorter control unit 212 performs control such as designation of apath for conveying a sheet and instruction to change the tray inaccordance with a control command received from the engine control unit209 in order to discharge the sheet to a tray of the sorter unit 114.The sorter control unit 212 can detect the presence of a sheet on a trayon the basis of the outputs of the sheet sensors on the trays. Thesorter control unit 212 also includes a CPU, ROM, and RAM, which areconnected via a system bus, like the main controller 201. In accordancewith a program stored in the ROM, the CPU controls processing using thesorter unit 114 as described above.

The host apparatus 215 corresponds to the external apparatus and isconnected to the image forming apparatus 200. The host apparatus 215supplies image data to be printed by the image forming apparatus 200 andissues various print job orders.

The host apparatus 215 may be implemented by a general-purpose personalcomputer (PC) or may be other types of data supply device. Other typesof data supply device may be an image capturing apparatus which capturesan image to generate image data. The image capturing apparatus may be areader (scanner) which scans an image on an original document andgenerates image data based on the scanned image or a film scanner whichreads a negative or positive film generates image data based on the readfilm. Other examples of the image capturing apparatus may include adigital camera which photographs a still image to generate digital imagedata and a digital video camera which captures a movie to generatemoving image data. Alternatively, a photo storage may be provided on anetwork, or the image forming apparatus may have a socket that receivesa movable portable memory. Thus, an image file stored in the photostorage or a portable memory may be read, and the image data may begenerated based on the read image file and printed therefrom. Instead ofthe general-purpose PC, a terminal that is special for the image formingapparatus may be used, or various data supply devices may be used. Thesedata supply devices may be a component or components of the imageforming apparatus or separate devices externally connected to the imageforming apparatus. When the host apparatus 215 is a PC, an OS,application software which generates image data, a printer driver forthe image forming apparatus 200 are installed in a storage device of thePC. The printer driver may control the image forming apparatus 200 andconverts image data supplied from the application software to a formatsupported by the image forming apparatus 200 to generate print data. Theconversion from print data to image data may be performed in the hostapparatus 215, and the resulting data may then be supplied to the imageforming apparatus 200. All of the processing operations described up tothis point are not required to implement by software, but a part or allof the processing operations may be implemented by hardware. The imagedata, other commands and status signals supplied from the host apparatus215 may be transmitted and received to and from the image formingapparatus 200 through the external I/F 205.

In the example above, each of the function blocks has a CPU, but thepresent invention is not limited thereto. Some of the function blocksmay not have a CPU but may operate under the control of the maincontroller 201 or the main controller 201 and engine control unit 209.The function blocks may be responsible for the operations in the wayexcluding the configuration illustrated in FIG. 2 so that they can beproperly divided into separate processing units or control units or someof them can be merged. The function blocks may have various forms. Adirect memory access controller (DMAC) may be used to read data frommemory.

Next, there will be described a flow of processing executing a print jobby the image forming apparatus 200 in this configuration. FIG. 3 is aflowchart illustrating a flow of processing for executing a print jobwhen the image forming apparatus 200 receives the print job in duplexprinting mode. The flowchart illustrates a flow of processing to beperformed by loading and executing a control program stored in the ROMor the HDD 206 into the RAM by the CPU of the function block illustratedin FIG. 2. A print job may contain print data, an output sheet sizeindicating the size after sheet cut, a sheet type indicating thematerial of the sheet (such as plain paper, glossy paper, coated paper,and a film), and a printing mode (such as one side printing, duplexprinting, and bookbinding printing). It is assumed that the size (rollwidth) and sheet type of the sheets set in the sheet cassettes 101 a and101 b are pre-stored in the RAM 204 or the RAM in the engine controlunit 209 by an operation by a user through the operating unit 115.

In S301, when a print job is received through the external I/F 205, theprint job is started to process. The received print job is once storedin the HDD 206. In S302, the order of printing pages for the receivedprint job is determined.

FIG. 4 is a flowchart illustrating details of the processing in S302.The processing in the flowchart is performed by loading and executing acontrol program stored in the ROM 203 or HDD 206 into the RAM 204 by theCPU 202.

The image forming apparatus 200 may perform a plurality of print jobscontinuously without cutting a sheet at the border of jobs (and mergingprint data). Whether merging print data of a plurality of print jobs ispermitted or not (ON/OFF as a merge setting) may be set by a user withthe operating unit 115. The set merge setting ON or OFF is stored in theRAM 204. In S401, the CPU 202 refers to the setting stored in the RAM204 and thus determines whether the merge setting is ON or not.

If the merge setting is OFF, the merging over a plurality of print jobsis not performed. Then, the processing moves to S402, and the CPU 202determines the order of printing pages in one print job. The order ofprinting pages is determined in accordance with the print layout (suchas settings (such as a binding method) in simplex printing, duplexprinting and bookbinding printing modes). In this case, the position tocut the sheet is determined in accordance with the print settings suchas the print layout and sheet type (including its size and sheet type).Here, the size refers to a two-dimensional size in ISO A series or Bseries, and the sheet type refers to the material of a sheet such asplain paper and glossy paper.

In order to print both sides of a sheet, the page order is determinedsuch that one side (first side) can be continuously printed, and theopposite side can then be printed continuously in the opposite sequenceof printing the first side. For example, in order to arrange print datapieces of Pages 1 to 6 to both sides of a sheet in an increasing orderof page numbers, images for Pages 1, 3, and 5 are first printedsequentially on the front surface of a sheet. Next, after the sheet isreversed, images for Pages 6, 4, and 2 are printed sequentially. Inorder to print the back surface first, the back surface is set as thefirst side, and images of Pages 6, 4, and 2 are sequentially printedthereon. After the sheet is reversed, images of Pages 1, 3, and 5 areprinted sequentially. In the latter case, sheets are discharged withtheir face down, like one side printing mode.

Printing in the page order requires reversing a sheet only once and canincrease the efficiency of the job processing. In bookbinding printingmode, though the arrangement order of pages may be different, the pageorder is determined so as to print one side continuously.

However, a different print setting (sheet type) between pages mayrequire changing the source of a sheet or replacing with another sheet.Thus, in duplex printing mode, it is determined that print data of pagesto be printed on the first side with the same print settings arearranged to print continuously. It is determined that the sheet is oncecut before the print setting is changed. It is determined that theopposite side is printed after that, a new sheet is fed, and theremaining print data is printed.

In this case, whether a setting relating to the sheet type among printsettings specified for a print job is the same or not is determined, andprinting is performed continuously even the other print settings aredifferent. In other words, whether the sheets to be used are the same ornot is determined by comparing the sheet types of neighboring images tobe arranged on the same side (first side) of sheets.

In order to print both sides of a sheet, the same print setting for theopposite side is required. The comparison between images on the firstsides is enough because an error occurs before the print job is startedwhen the print setting for the first side and the print setting for theopposite side are different in sheet type, for example.

Having described above that the print settings relating to the sheettype are compared, a difference may be determined in other settings(such as an image quality mode) if the difference does not allowcontinuous printing.

If it is determined in S401 that the merge setting is ON, the processingmoves to S403 where the CPU 202 detects the remaining amount of thesheet to be used for the current printing processing. More specifically,the remaining amount may be detected on the basis of the diameter (orradius) of the roll of the sheet to be used for the current printingprocessing, which is set in the cassette 101 a or 101 b or thedifference in count value between the length of the sheet when it is setand the length of the sheet used before this time, for example. Thedetection result is preferably the length not exceeding the actualremaining amount. The detected remaining amount is stored in the RAM204.

In S404, the CPU 202 determines whether images for a plurality of pagesto be arranged on the first side of the accepted one or plurality ofprint jobs have the same printing setting or settings over the length ofthe remaining amount of the sheet detected in S403 and additional regionα or not. Neighboring images to be arranged on the same side of thesheet are to be compared, and images to be compared are sequentiallychanged. The print setting for the comparison in S404 may be a usablesheet size, and/or a sheet type to be used, like the comparison withinone job. The print layout may vary. The length of the images across aplurality of pages may include the length of the margins of pages ifthey are provided between pages. The print data corresponding to thedetected remaining amount of sheet ends at a page break and may bedifferent from the remaining amount detected in S403 for some kinds ofprint job. The additional region α is longer than a predetermined lengthA and shorter than another predetermined length B (A<B) and has its endat a page break. The additional region α may be one page or a pluralityof pages for some kinds of print job. The length of the additionalregion α may be determined in accordance with the detected remainingamount of a sheet or other conditions.

In S405, the CPU 202 determines whether pages for the remaining amountof sheet+α are mergeable or not. It is determined with reference to thefollowing (1) and (2): (1) The length of the sheet to be used for themerged pages does not exceed a predetermined length. This is forpreventing excessive delay of output of the preceding print job induplex printing mode. (2) A tray of the sorter unit 114 is available forthe merged pages. This is for preventing delay of printing due tounavailability of a tray. A group of images of a plurality of pages tobe arranged on the same surface and to be printed continuously will becalled a job group. In printing one job group, a sheet is not cut whilethe same surface is being printed but is kept being printed(continuously). If it is determined that the pages are mergeable, theprocessing moves to S406 where the print data corresponding to thedetected remaining amount of the sheet and the print data correspondingto the additional region α are merged (made continuous) to generate onejob group. Within the generated job group, the page order is determinedin accordance with the printing mode. In duplex printing mode, theprinting order (page order) of images to be arranged on the oppositeside is also determined. In S407, the print data for the additionalregion α is also repeated (assigned) to the next job group. In otherwords, the print data for α is repeated in the two preceding andsubsequent job groups.

If it is determined in S407 that the print settings (sheet type) for allof the remaining amount of sheet+α are not the same (including evenpartial pages not having the same print setting), the processing movesto S408 where the CPU 202 merges the print data for pages with the samesetting from the beginning to generate one job group. Before merging,the mergeability is also determined here like S405, but the detaildescription will be omitted. If none of the pages have the same printsetting, the pages are not merged. The rest of the pages not merged tothe previous job group among the pages to be processed in S409 aremerged into the next job group. The print data for the additional regionα is not added here. Then, the printing order within each job group isdetermined.

Also if it is determined in S405 that the pages are not mergeable, printdata for pages having the same print setting are merged from thebeginning, and the print data for the rest of the pages are shifted tothe next job group in S410 and 411, as in S408 and 409. In theprocessing in FIG. 4, when the external I/F 205 is a network I/F,various print jobs issued from various users of a plurality of hostapparatuses present on a network are to be merged.

If the order of printing pages is determined in this way, the processingmoves to S303, and the first side (which is the front surface here) ofthe sheet is started to print. In other words, in the determinedprinting order, the CPU 202 supplies the print data for the pages to theimage processing unit 207. The CPU of the image processing unit 207converts the print data to be printed on the front surface to aprintable form (expansion to image data) and stores the image data tothe HDD 206. The generated image data is supplied to the engine controlunit 209 in the page order. Here, the side of the sheet to print theimage data, page numbers, and information from which the print job canbe identified are also notified in addition to image data to the enginecontrol unit 209.

The CPU of the engine control unit 209 having received the image datacauses the sheet cassette 101 a or 101 b based on the size of the imagesto be printed and the sheet type of the sheet to feed the sheet. The CPUof the engine control unit 209 causes the conveying unit 102 to conveythe sheet to the print position by the head unit 105, sequentiallyprints the images based on the image data on the front surface of thesheet, and causes to conveys the sheet to the scanning position by thescanner unit 107. Whether the images have properly been printed or notis checked on the basis of the content of the image data which isacquired by scanning the printed images by the scanner unit 107, and thesheet is conveyed toward the cutter unit 110. If it is determined thatthe images have properly been printed, the sheet is not cut by thecutter unit 110 into page units. The sheet having continuous pages ispassed through the drying unit 112, and the ink on the sheet is dried.Then, the sheet is wound by the sheet winding unit 113. On the otherhand, if it is determined that the images have not properly beenprinted, the CPU of the engine control unit 209 causes the cutter unit110 to cut the page which has not correctly printed to discharge it. Thecut sheet is discharged to a tray (such as the lowest tray) thatdischarges a defective among the trays of the sorter unit 114. In orderto re-print the print data which have not properly been printed, the CPU202 supplies the image data to the engine control unit 209 again andrepeats the subsequent operations.

In this way, in parallel with printing images on the front surface inS303, the CPU of the engine control unit 209 determines the presence ofan additional page in S304. Even during printing in the previouslydetermined printing order, the image forming apparatus 200 receives newprint jobs sequentially and stores them in the HDD 206. It is moreefficient to also print them continuously. The presence of an additionalpage may be determined in the same manner as S302 (FIG. 4). If it isdetermined that an additional page exists, the print page is added tothe job group in S305, and the processing continues until the printingon the front surface finishes.

If printing all pages completes on the front surface in S303, and it isdetermined that no additional page exists, the processing moves to S306where the CPU of the engine control unit 209 causes the cutter unit 110to cut the sheet having its front surface printed. In S307, the sheethaving its front surface printed wound by the sheet winding unit 113 isre-conveyed by the conveying unit 102 such that the opposite side of thefirst side directs toward the head unit 105. In S308, the back surfaceis printed. Since the printing on the back surface is performed in thesame manner as the front surface, the detail description will beomitted. However, after printing on the back surface, the sheet is cutby the cutter unit 110 into page units (or may be cut into unitscorresponding to two pages in bookbinding printing mode). The cut sheetsare discharged to a tray of the sorter unit 114.

In order to execute the subsequent print job which has been determinedto shift to another job group on the basis of the processing in FIG. 4,the flow in FIG. 3 is repeated on the print jobs stored in the HDD 206.The sheet to be used in this case is fed from the cassette which is notused in the previous print job or is a sheet newly set in the cassetteused by the previous print job. However, the processing up to theoperation by the image processing unit 207 for the subsequent job groupis performed in parallel with the printing processing on the previousjob group. Thus, since the engine control unit 209 can continuouslyperform processing for a plurality of job groups, many print jobs can beexecuted efficiently.

FIG. 6B illustrates the printing order to be performed when pages aremerged by the processing above. It is assumed that a job A, a job B, anda job C which are different print jobs from each other are input, and itis instructed to execute the jobs in the arrangement as illustrated inFIG. 6B. It is further assumed that the pages to be arranged on the sameside of a sheet have the same print setting regarding the sheet type.

When the operations in FIGS. 3 and 4 are performed to merge the pages(generate a job group), the pages are printed in the following order.That is, the pages are printed in order of the first page of the job A,the third page of the job A, the first page of the job B, . . . , andthe third page of the job C are printed. The sheet is cut, and the cutsheets are reversed. Then, the pages are printed in order of the fourthpage of the job C, the second page of the job C, . . . , and the secondpage of the job A. Thus, executing three print jobs only requires thesheet to be cut and reversed once until beginning printing the pages forthe back surface of the sheet.

On the other hand, without the processing in FIGS. 3 and 4, printing isperformed on one print job unit in the order as illustrated in FIG. 6A.That is, the first page and the third page of the job A are printed, andthe sheet is cut and the cut sheets are reversed. Then, the fourth pageand the second page are printed. In this case, in the sheet cassettehaving fed the sheet for the job A, the sheet is wound back after thesheet cut. After that, the sheet is started to feed again for executionof the job B, and the first page and the third page of the job B areprinted. The sheet is cut, and the cut sheets are reversed. Then, thefourth page and the second page are printed. Then, the sheet is woundback and is fed again to perform the processing also for the job C.Thus, the execution of the three print jobs requires cutting andreversing the sheet three times, and re-winding and re-feeding areperformed at least twice.

In this way, according to this embodiment, the numbers of times of cut,reverse, re-winding, and re-feeding of a sheet can be reduced as few aspossible, and a plurality of print jobs can be significantly efficientlyperformed.

Next, the processing will be described in the case where the sheet runsout during the printing processing on the first side in S303. FIG. 5 isa flowchart illustrating details of the processing in this case. Theprocessing in the flowchart is implemented by loading and executing bythe CPU of the engine control unit 209 a control program stored in theROM or HDD 206 in the engine control unit 209 to the RAM of the enginecontrol unit 209. Here, with reference to the flowchart in FIG. 4, thecase will be described in which one job group is generated in S405 fromprint data for the remaining amount+α.

The printing processing starts in S501, and whether printing images forthe number of pages to be arranged on the first side of the sheet in onejob group has completed or not is determined in S502. If so, theprocessing moves to S306 in FIG. 3 where the opposite side is printed.If not, the processing moves to S503 where whether the sheet runs outduring the printing processing or not is determined. If not, theprinting processing continues in S501.

If it is determined in S503 that the sheet runs out during the printingprocessing, the processing moves to S504 where the last printed page inthe job group generated in S406 is identified. The printed page refersto one having the entire image for one page printed properly. Theinformation on the printed page identified here is stored in the RAM ofthe engine control unit 209.

In S505, when the sheet runs out at some point of a page being printed,resulting in an incomplete page, the sheet is cut at the page break ofthe previous page by the cutter unit 110. The sheet having theincomplete page printed is only discharged to a tray for discharging adefective in the sorter unit 114. When the printing processing is to beperformed over the end of the sheet and if the rest of the sheet isshorter than the length for one page, the last page may not be printed.When images are normally printed on the first side of the sheet, thereversed sheet is re-conveyed from the sheet winding unit 113, and theopposite side is printed in S506. Here, in accordance with the last pageprinted on the first side, the previously determined order of printingpages is changed. In other words, the printing order is determined suchthat the image of the page on the opposite side corresponding to thepage printed properly on the first side can be printed in the reverseorder of the first side.

After the opposite side is printed, the processing moves to S507 wherewhether a sheet having the same size (roll width) and the same sheettype as the sheet having been determined as running out in S503 is setin the other cassette or not is determined. In other words, when thecassette 101 a has supplied the sheet having been determine as runningout in S503, whether the type of the sheet set in the cassette 101 b isthe same as that in the cassette 101 a or not is determined. When thecassette 101 b has supplied the sheet having been determined as runningout in S503, whether the type of the sheet set in the cassette 101 a isthe same as that in the cassette 101 a or not is determined.

If it is determined that a sheet having the same size and sheet type isset in the other cassette, the cassette that has supplied the sheet isswitched to the other in S508. Then, the processing returns to S501where the remaining pages (next job group) are printed. However, printdata for α is added at the beginning of the next job group, and a partof the print data has already been properly printed. Thus, withreference to the information identified in S504, printing is performedfrom the subsequent page. In other words, the print data for the pageshaving properly been printed are skipped from the beginning of the printdata for α, and printing on the first side starts from the print datawhich have not been printed for full one page. After that, thesubsequent print data is printed, and the processing moves to printingon the opposite side.

If it is determined in S507 that a sheet having the same size and sheettype is not set in the other cassette, the processing moves to S509where the CPU 202 instructs the operating unit 115 to prompt to replacethe sheet and indicate the size and sheet type of the sheet to be set.When the applicable sheet is set in one of the cassettes, the printingprocessing continues the processing from S501.

FIG. 7 schematically illustrates print data to be arranged on the firstside in the job group generated in S405 and print data to be arranged onthe first side in the next job group.

In FIG. 7, print data 701 corresponds to the detected remaining amountof the sheet, and print data 702 corresponds to the additional region α.The print data 701 and 702 are included in one job group. A region 703is identified in S504 as having been properly printed. Printing has beenproperly performed in the previous job group up to a page break position704, and the position 704 corresponds to the page position to startprinting in the next job group. A print page 705 is the same as theprint page having the page break position 704 and is followed bysubsequent print data 706. The print page 705 and 706 are included inthe next job group to be performed after the cassette change or sheetreplacement.

Having described above that a plurality of print jobs in duplex printingmode are merged, for example, a print job in duplex printing mode and ajob in one side printing mode may be merged, or a plurality of jobs inone side printing mode may be merged. In order to merge a plurality ofprint jobs even in one side printing mode, the efficiency of theprocessing may be increased by rewinding the sheet and reducing thenumber of times of re-feeding.

Having described that print jobs with print setting of the same size andsheet type are merged, the print jobs to be merged may have differentsize settings only. Since the sheet printed a smaller size image may becut along both sides after the sheet is discharged, print jobs may bemerged when the size of the sheet of the subsequent print job is smallerthan the size of the sheet of the preceding print job. In other words,in the example in FIG. 6A or 6B, jobs A, B and C may be merged to onejob group if the sheet size for the job A is A4, the sheet size for thejob B is B5, and the sheet size for the job C is A4. When a plurality ofsheet sizes are available for the subsequent print job, the sheet sizethat is the same as that of the sheet for the preceding print job isdetermined to apply among the plurality of sheet size, and the printjobs may be merged into one job group. The same is true for sheet types.When a job group is to be determined before starting the preceding printjob and if a plurality of sheets are available for the preceding printjob and subsequent print job, the print jobs may be merged into the samejob group with the use of the sheets matched with each other.

In the processing described above, priority levels may be assigned toprint jobs, and the printing order and/or mergeability may be changed inaccordance with the priority levels. For example, if the preceding printjob has a higher priority level and the subsequent print job has a lowerpriority than the preceding one, the subsequent print job is not mergedso that the print job with a higher priority level can be completedearlier.

Having described above that the mergeability is determined in page unitsto merge jobs, the mergeability may be determined in job units to mergeor not to merge jobs for preventing a print job from being separated atsome point in the print job. In other words, some print job does notinclude pages having different sheet type between pages but includes allpages having the same sheet type. In this case, the mergeability may bedetermined in job units.

In the processing described above, the printing order is not limited tothe order illustrated in FIG. 6B. The printing order may vary inaccordance with the mechanism and discharging method of the imageforming apparatus 200. In all cases, images for a plurality of printjobs are printed on the first side, and images are then printed on theopposite side.

According to this embodiment, the efficiency of processing may beincreased by rewinding a sheet and reducing the number of times ofre-feeding. Even when a sheet runs out, the print data to be printedafter the change of the feeding cassette or sheet replacement may beprepared in advance. Thus, the printing after the change of the feedingcassette or sheet replacement can be performed efficiently. Furthermore,the sheet can be used without waste. Even when the remaining amount ofthe sheet is not accurately detected, the sheet can be used withoutwaste.

Having described with reference to FIG. 4 that the remaining amount ofthe sheet is detected before printing is started, and, on the basis ofthe result of the detection, the print data for the additional region αis set at the end of the preceding job group and the beginning of thenext job group, the present invention is not limited thereto. When it isdetermined during printing processing that the end of the sheet isapproaching, the print data corresponding to the end may be also addedto the beginning of the next print data (print data to be printed afterthe cassette change or sheet replacement) as additional region, and theprocessing may be performed as in FIG. 5. Also in this case, since printdata for the next job group may be prepared in advance, printing can bestarted immediately after the cassette change or sheet replacement.

It has been assumed above that the print data for α extends beyond theend of the sheet. However, when the sheet runs out before the print datafor α is started to print, the print data for the page which has notbeen printed for that reason may be added to the beginning of the nextjob group to print.

In all cases, the print data to be printed at the end of the sheet isalso assigned to the beginning of the print data for the sheet after thecassette change or sheet replacement. In accordance with the printcondition for the previous sheet, the starting page may be determinedfor printing on the sheet after the cassette change or sheetreplacement. The assignment of the print data for the sheet after thecassette change or sheet replacement to the beginning is preferablyperformed before the completion of the printing on the sheet before thecassette change or sheet replacement.

In the processing described above, the processing such as schedulingbased on the printing order, determination on mergeability, and settingof an additional region, excluding the printing processing, may beimplemented by an external apparatus such as a host apparatus and anexternal controller, and, on the basis of the results of the processing,the image forming apparatus may be caused to implement the printing. Theexternal apparatus preferably acquires a status or statuses (informationsuch as the current print condition and the remaining amount of thesheet) from the image forming apparatus to determine the printing orderand/or mergeability. In this case, the external apparatus functions as aprint control apparatus.

The present invention is implemented by the following processing:Software (program) which implements the functions of the embodiment issupplied to a system or an apparatus through a network or a storagemedium, and a computer (or CPU, MPU or the like) of the system orapparatus reads the program and thus performs the processing. Theprogram may be executed by one computer or a plurality of computers inconjunction. Not all of the processing operations are required toimplement by software, but a part or all of the processing operationsmay be implemented by hardware.

The present invention is not limited to the embodiment, but variouschanges (including the application to other embodiments and combinationswith other embodiments) are possible on the basis of the spirit of thepresent invention.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

1. (canceled)
 2. A print control apparatus capable of causing a printingunit to print on a continuous sheet, the apparatus comprising: agenerating unit configured to generate print data to be printed on acontinuous sheet, and a print control unit configured to cause theprinting unit to print an image based on the print data generated by thegenerating unit on the continuous sheet, wherein the generating unitgenerates print data, in beginning of which image data arranged at anend of a first continuous sheet is arranged, to be printed on a secondcontinuous sheet.
 3. The print control apparatus according to claim 2,further comprising an identifying unit configured to identify a regionin the image based on the print data properly printed on the firstcontinuous sheet by the printing unit, wherein the print control unitcauses the printing unit to start printing from the region following theregion identified by the identifying unit in the image based on theprint data generated by the generating unit on the second continuoussheet.
 4. The print control apparatus according to claim 2, furthercomprising: a detecting unit configured to detect the remaining amountof the first continuous sheet, wherein the generating unit generatesprint data, in beginning of which image data arranged at an end of thefirst continuous sheet is arranged, to be printed on the secondcontinuous sheet in accordance with the remaining amount of the firstcontinuous sheet detected by the detecting unit.
 5. The print controlapparatus according to claim 2, further comprising: a detecting unitconfigured to detect, during a printing processing, whether the end ofthe first continuous sheet is in the vicinity thereof, wherein thegenerating unit generates print data, in beginning of which image dataarranged at an end of the first continuous sheet is arranged, to beprinted on the second continuous sheet if the detecting unit detectsthat the end of the first continuous sheet is in the vicinity thereof.6. The print control apparatus according to claim 2, wherein the printcontrol unit causes the printing unit to print both sides of acontinuous sheet by continuously printing a plurality of images of aplurality of print jobs to be arranged on a first side of the continuoussheet and then continuously printing a plurality of images of theplurality of print jobs to be arranged on the opposite side of thecontinuous sheet.
 7. The print control apparatus according to claim 2,further comprising: a determining unit configured to determine whether acontinuous sheet usable for printing by the printing unit based on firstprint data and a continuous sheet usable for printing by the printingunit based on second print data are the same or not, wherein the printcontrol unit, if the determining unit determines that they are the same,causes the printing unit to print an image based on the first print dataand an image based on the second print data continuously on a continuoussheet.
 8. The print control apparatus according to claim 2, wherein thefirst continuous sheet is supplied from a sheet supplying unit and thesecond continuous sheet is newly set to the sheet supplying unit orsupplied from a second sheet supplying unit which is different from thesheet supplying unit.
 9. A print control method comprising: generatingprint data to be printed on a continuous sheet, causing a printing unitto print an image based on the generated print data on a continuoussheet; wherein the print data, in beginning of which image data arrangedat an end of a first continuous sheet is arranged, to be printed on asecond continuous sheet is generated.
 10. A non-transitorycomputer-readable storage medium storing a computer-executable program,the program comprising: generating print data to be printed on acontinuous sheet, causing a printing unit to print an image based on thegenerated print data on a continuous sheet, wherein the print data, inbeginning of which image data arranged at an end of a first continuoussheet is arranged, to be printed on a second continuous sheet isgenerated.
 11. The print control apparatus according to claim 9, furthercomprising: an identifying unit configured to identify a region in theimage based on the print data properly printed on the first continuoussheet by the printing unit, wherein the print control unit causes theprinting unit to start printing from the region following the regionidentified by the identifying unit in the image based on the print datagenerated by the generating unit on the second continuous sheet.
 12. Themethod according to claim 9, further comprising: detecting the remainingamount of the first continuous sheet, wherein the generating generatesprint data, in beginning of which image data arranged at an end of thefirst continuous sheet is arranged, to be printed on the secondcontinuous sheet in accordance with the remaining amount of the detectedfirst continuous sheet.
 13. The method according to claim 9, furthercomprising: detecting, during a printing processing, whether the end ofthe first continuous sheet is in the vicinity thereof, wherein thegenerating generates print data, in beginning of which image dataarranged at an end of the first continuous sheet is arranged, to beprinted on the second continuous sheet if the end of the firstcontinuous sheet is in the vicinity thereof is detected.
 14. The methodaccording to claim 9, wherein the printing causes the both sides of acontinuous sheet by continuously printing a plurality of images of aplurality of print jobs to be arranged on a first side of the continuoussheet and then continuously printing a plurality of images of theplurality of print jobs to be arranged on the opposite side of thecontinuous sheet.
 15. The method according to claim 9, furthercomprising: determining whether a continuous sheet usable for printingbased on first print data and a continuous sheet usable for printingbased on second print data are the same or not, wherein the printcontrol unit, if the determining unit determines that they are the same,causes the printing to print an image based on the first print data andan image based on the second print data continuously on a continuoussheet.
 16. The method according to claim 9, wherein the first continuoussheet is supplied from a sheet supplying unit and the second continuoussheet is newly set to the sheet supplying unit or supplied from a secondsheet supplying unit which is different from the sheet supplying unit.